Passive natural circulation lead-bismuth aeration device and aeration method

Abstract

The present invention discloses a passive natural circulation lead-bismuth gasification device and a gasification method. The device can be installed on a lead-bismuth alloy passive natural circulation device to provide mixed gases with different proportions for the lead-bismuth alloy in the lead-bismuth alloy passive natural circulation device, or to provide mixed gases at different pressures and flow rates, thereby facilitating the study of the influence of different mixed gases, different pressures and different flow rates on the passive natural circulation capacity of the lead-bismuth alloy.

Description

Technical Field

[0001] The invention relates to the field related to nuclear energy equipment, and in particular to a passive natural circulation lead-bismuth gasification device and a gasification method. Background Art

[0002] ADS (accelerate driven system) is one of the most promising transmutation technologies. The ADS device consists of a medium-energy high-current proton accelerator, an external neutron production target and a subcritical reactor. It is an efficient nuclear waste transmutation furnace. The basic principle of ADS is as follows: the proton beam generated by the accelerator bombards the heavy metal target in the subcritical reactor, causing a spallation reaction, and then produces neutrons through the intranuclear cascade and the extranuclear cascade. The spallation neutron target provides external neutrons for the subcritical reactor. In ADS, liquid lead-bismuth alloy (PbBi) is used as a spallation target and coolant. In addition to having good neutronic properties, it also has excellent radiation resistance, heat transfer performance and safety characteristics, which can improve the life of the target system and the safety of the subcritical reactor.

[0003] Lead-bismuth alloy is an important cooling material, and its thermal hydraulic properties are very important for the experimental bench or core to be built, which can ensure the normal heat extraction. Although there are reports on the research of lead-bismuth circulation flow heat transfer, they mainly focus on the impact on heat transfer performance. There are few studies on passive natural circulation, and there are few related studies on lead-bismuth gasification devices, and there is no research on the impact of gas type, amount and other parameters on the natural circulation effect.

[0004] Due to the above reasons, the inventors have designed an auxiliary device to solve the problem of natural circulation of lead-bismuth alloy, which can assist in analyzing the factors affecting the flow and heat exchange capacity of passive natural circulation lead-bismuth alloy. Summary of the invention

[0005] In order to overcome the above-mentioned problems, the inventors have conducted intensive research and designed a passive natural circulation lead-bismuth gasification device, which can be installed on a lead-bismuth alloy passive natural circulation device to provide mixed gases of different proportions to the lead-bismuth alloy in the lead-bismuth alloy passive natural circulation device, or to provide mixed gases at different pressures and flow rates, thereby facilitating the study of the effects of different mixed gases, different pressures and different flow rates on the passive natural circulation capacity of the lead-bismuth alloy.

[0006] Specifically, the object of the present invention is to provide a passive natural circulation lead-bismuth gasification device, the device comprising a gas circulation pipeline, the gas circulation pipeline being installed on a lead-bismuth alloy circulation pipeline;

[0007] A lead-bismuth alloy coolant flows in the lead-bismuth alloy circulation pipeline, and a heater and a heat exchanger are arranged on the lead-bismuth alloy circulation pipeline;

[0008] The gas circulation pipeline comprises a temperature rising section, a hot gas section, a temperature falling section and a cold gas section which are connected in sequence;

[0009] The temperature rising section is installed in the rising section of the lead-bismuth alloy circulation pipeline and is located after the heater;

[0010] The cooling section is installed in the descending section of the lead-bismuth alloy circulation pipeline and is located after the heat exchanger;

[0011] The hot gas section passes through the wall of the lead-bismuth alloy circulation pipeline, one end of which is sealed and connected to the top of the temperature rising section, and the other end of which is sealed and connected to the top of the temperature falling section;

[0012] The cold air section passes through the wall of the lead-bismuth alloy circulation pipeline, one end of which is sealed and connected to the bottom end of the temperature rising section, and the other end of which is sealed and connected to the bottom end of the temperature falling section;

[0013] An air inlet is provided on the temperature rising section.

[0014] A gas collecting pipe opening is provided on the cold air section.

[0015] Gas is injected into the gas circulation pipeline through the air inlet pipe port, and the gas in the gas circulation pipeline is discharged through the gas collecting pipe port.

[0016] The device further comprises an air intake pipe and an air collecting pipe, wherein an air intake system, an air intake check valve and a pump are sequentially arranged on the air intake pipe, and the air intake pipe is connected to the air intake pipe port;

[0017] An air collecting system, an air outlet check valve and an exhaust fan are sequentially arranged on the air collecting pipeline; the air collecting pipeline is communicated with the air collecting pipe port.

[0018] Wherein, the composition ratio of the gas is adjusted through the air intake system.

[0019] Wherein, the air intake system comprises a gas cabinet and a mixing chamber;

[0020] The gas cabinet is connected to the mixing chamber through a pipeline, and an air intake check valve and a pressure reducing valve are arranged on the pipeline;

[0021] There are multiple gas cabinets, each of which stores a type of gas, and the types of gases in different gas cabinets can be the same or different;

[0022] The multiple gas cabinets inject gas into the mixing chamber one by one;

[0023] A pressure indicator is arranged on the mixing chamber; the pressure indicator is used to output the pressure value on the mixing chamber in real time, so as to adjust the proportion of the mixed gas according to the data of the pressure indicator.

[0024] Wherein, the gas in the gas circulation pipeline is collected and stored by the gas collection system.

[0025] Wherein, the gas collection system comprises a separation chamber and a storage bottle, and a gas collection check valve is arranged between the separation chamber and the storage bottle;

[0026] Preferably, a plurality of storage bottles are provided, which are respectively connected to different positions of the separation chamber through pipelines.

[0027] Wherein, a permeable membrane is arranged in the separation chamber; the separation chamber is divided into a plurality of independent spaces connected in sequence by the permeable membrane, and each of the independent spaces is connected to at least one storage bottle.

[0028] The present invention also provides a passive natural circulation lead-bismuth gasification method.

[0029] The gas in the mixing chamber passes through the intake check valve and the pump and then enters the temperature rising section of the gas circulation pipeline through the intake pipe opening;

[0030] The gas moves upward in the temperature rising section of the circulation pipeline and is heated by the lead-bismuth alloy in the lead-bismuth alloy circulation pipeline, then passes through the hot gas section and the temperature falling section in sequence, is cooled in the temperature falling section, and finally returns to the temperature rising section via the cold gas section, thereby circulating in the gas circulation pipeline;

[0031] When the gas in the gas circulation pipeline needs to be exhausted, the gas outlet check valve and the exhaust fan on the gas collection pipeline are opened, so that the gas in the gas circulation pipeline enters the gas collection system through the gas collection pipe opening.

[0032] Wherein, the gas in the mixing chamber is configured by the following steps:

[0033] Step a, injecting gas from a gas cabinet into a mixing chamber through a pressure reducing valve, and recording the pressure value in the mixing chamber through a pressure indicator;

[0034] Step b, injecting the gas in another gas cabinet into the mixing chamber through another pressure reducing valve, and then recording the pressure value in the mixing chamber through a pressure indicator, and calculating the mass ratio of the mixed gas in the mixing chamber according to the change in the pressure value.

[0035] The gas entering the gas collection system is processed as follows:

[0036] The control gas passes through multiple separation chambers in the gas collection system in sequence. After all the gases in the gas collection pipeline enter the separation chambers, the gas in the separation chamber farthest from the gas inlet end of the gas collection system is first injected into the storage bottle, and then the gas in the separation chamber adjacent to the farthest separation chamber is collected, and so on, and finally the gases in all the separation chambers are collected into different storage bottles.

[0037] The passive natural circulation lead-bismuth gasification device provided by the present invention is provided with an air intake system, which can quickly and accurately configure a mixed gas with a desired ratio, and inject it into the circulation pipeline for experimental operation, so as to examine the influence of gases with different ratios on the passive natural circulation of lead-bismuth alloy, and can provide basic research data for specific reactor design. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram showing the overall structure of a passive natural circulation lead-bismuth gasification device according to a preferred embodiment of the present invention is shown;

[0039] Figure 2 A schematic diagram of the structure of an air intake system according to a preferred embodiment of the present invention is shown;

[0040] Figure 3 A schematic diagram of the structure of a gas collection system according to a preferred embodiment of the present invention is shown.

[0041] Description of Figure Numbers:

[0042] 11- Heating stage

[0043] 12-Hot gas section

[0044] 13- Cooling stage

[0045] 14- Air conditioning section

[0046] 2-Inlet pipe

[0047] 3-Gas collecting pipe opening

[0048] 4-Intake system

[0049] 41-Gas Cabinet

[0050] 42-Intake check valve

[0051] 43-Pressure reducing valve

[0052] 44-Mixing chamber

[0053] 45-Pressure indicator

[0054] 5-Intake check valve

[0055] 6-Pump

[0056] 7-Gas Collection System

[0057] 71-Separation Chamber

[0058] 72-Storage Bottle

[0059] 73-Gas collecting check valve

[0060] 74-Permeable membrane

[0061] 8-Exhaust check valve

[0062] 9-Exhaust fan DETAILED DESCRIPTION

[0063] The present invention will be further described in detail below through the accompanying drawings and embodiments. Through these descriptions, the characteristics and advantages of the present invention will become more clear and distinct.

[0064] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0065] According to the passive natural circulation lead-bismuth gasification device provided by the present invention, Figure 1 As shown in , the device includes a gas circulation pipeline, which is installed on the lead-bismuth alloy circulation pipeline; the lead-bismuth alloy circulation pipeline is independently sealed, and the lead-bismuth alloy circulates therein; the gas circulation pipeline is independently sealed, and other circulation flows therein. The diameter of the gas circulation pipeline is relatively small, and the outer diameter of the gas circulation pipeline is less than one tenth of the inner diameter of the lead-bismuth alloy circulation pipeline, which basically does not block the normal circulation of the lead-bismuth alloy.

[0066] A lead-bismuth alloy coolant flows in the lead-bismuth alloy circulation pipeline, and a heater and a heat exchanger are arranged on the lead-bismuth alloy circulation pipeline;

[0067] The gas circulation pipeline includes a temperature rising section 11, a hot gas section 12, a temperature falling section 13 and a cold gas section 14 which are connected in sequence;

[0068] The temperature rising section 11 is installed in the rising section of the lead-bismuth alloy circulation pipeline and is located after the heater. By setting the temperature rising section 11, the overall average density in the rising section of the lead-bismuth alloy circulation pipeline is reduced, thereby affecting the flow properties of the lead-bismuth alloy through the density, promoting the natural circulation of the lead-bismuth alloy, and ensuring that the nuclear reaction can continue safely and effectively.

[0069] The cooling section 13 is installed in the descending section of the lead-bismuth alloy circulation pipeline and is located after the heat exchanger;

[0070] The hot gas section 12 passes through the wall of the lead-bismuth alloy circulation pipeline, one end of which is sealed and connected to the top of the temperature rising section 11, and the other end of which is sealed and connected to the top of the temperature falling section 13;

[0071] The cold air section 14 passes through the wall of the lead-bismuth alloy circulation pipeline, one end of which is sealed and connected to the bottom end of the temperature rising section 11, and the other end of which is sealed and connected to the bottom end of the temperature falling section 13;

[0072] An air inlet port 2 is provided on the temperature rising section 11.

[0073] The cooling section 14 is provided with an air collecting pipe opening 3.

[0074] Gas is injected into the gas circulation pipeline through the air inlet pipe port 2 , and the gas in the gas circulation pipeline is discharged through the gas collecting pipe port 3 .

[0075] The passive natural circulation lead-bismuth heat exchange device described in the present invention is a nuclear reactor cooling circulation device already available in the prior art, which is recorded in the patent document entitled Passive Natural Circulation Lead-Bi Heat Exchange Device with application number 201120502918.8. It can also be a simulation device used in the laboratory, which aims to study the effects of different mixed gas ratios, pressures, and flow rates on the fluidity and heat transfer properties of lead-bismuth alloy. In a preferred embodiment, the device also includes an air intake pipe and a gas collection pipe, wherein an air intake system 4, an air intake check valve 5, and a pump 6 are sequentially arranged on the air intake pipe, and the air intake pipe is connected to the air intake pipe port 2 to inject gas into the gas circulation pipe. The gas is the gas configured by the air intake system, which can be selected according to specific test needs, and can be either a single gas or a mixed gas of a specific proportion;

[0076] The gas collecting pipe is sequentially provided with a gas collecting system 7, a gas outlet check valve 8 and an exhaust fan 9; the gas collecting pipe is connected with the gas collecting pipe port 3, and gas is extracted from the gas circulation pipe through the gas collecting pipe to achieve the purpose of exhausting / clearing the gas circulation pipe, and the gas circulation flow in the gas circulation pipe can also be promoted by collecting the extracted gas through the gas collecting pipe.

[0077] Preferably, the pressure in the air intake pipe is normal pressure relative to the lead-bismuth alloy fluid, and the gas injection flow rate is 0.001-0.01 kg / s.

[0078] In a preferred embodiment, the velocity of the gas injected into the gas circulation pipeline at the air inlet port 2 can be controlled at 2 m / s-5 m / s.

[0079] In a preferred embodiment, the composition ratio of the gas is adjusted by the air intake system 4, that is, the composition ratio of the gas injected into the gas circulation pipeline is adjusted.

[0080] The gas collection system 7 is used to collect and purify the gas after the experiment. The first step is to open the gas outlet check valve 8 and the exhaust fan 9 set in the pipeline to pass the gas in the gas circulation pipeline into the gas collection system 7. The second step is to use the multi-layer permeable membrane set in the gas collection system 7 to separate the gas, and use the different relative permeation rates of various gases to the membrane to achieve the purpose of separating the gas. The third step is to detect the purity of each layer of gas through an analyzer, and when the test is qualified, that is, the purity reaches more than 99%, it will be transported to the storage bottle 72.

[0081] In a preferred embodiment, Figure 2 As shown in , the air intake system 4 includes a gas cabinet 41 and a mixing chamber 44; the gas cabinet 41 is connected to the mixing chamber 44 through a pipeline, and an air intake check valve 42 and a pressure reducing valve 43 are provided on the pipeline;

[0082] There are multiple gas cabinets 41, each of which stores a gas. The types of gases in different gas cabinets 41 can be the same or different. Among them, there are at least three gas cabinets 41, each of which stores a gas, such as helium, argon or nitrogen.

[0083] By setting the air inlet check valve 42, it is ensured that the gas in the gas cabinet 41 can enter the mixing chamber 54, but the gas in the mixing chamber 44 cannot reversely enter the gas cabinet 41; by setting the pressure reducing valve, the pressure of the gas entering the mixing chamber 54 can be adjusted, thereby realizing the control of the gas introduction amount and proportion.

[0084] The pressure indicator 45 is installed on the mixing chamber 44 to output the pressure value on the mixing chamber 44 in real time, so as to adjust the ratio of the mixed gas according to the data of the pressure indicator 45 .

[0085] The multiple gas cabinets 41 inject gas into the mixing chamber 44 one by one, that is, at any time, at most one gas cabinet 41 is injecting gas into the mixing chamber 44, and there cannot be a situation where two or more gas cabinets inject gas into the mixing chamber at the same time, thereby realizing the gas ratio in the mixing chamber by reading the pressure value of the mixing chamber 44.

[0086] In a preferred embodiment, the multiple gas cabinets 41 inject gas into the mixing chamber 44 separately, and control the flow rate by pressure difference to achieve proportional control of the mixed gas components. Specifically, when the temperature of the control system remains unchanged, the gas A in the first gas cabinet 41 enters the mixing chamber 44 in a vacuum state through the line due to the pressure difference generated by the pressure reducing valve, and the pressure PA of the mixing chamber at this time is recorded by the pressure indicator 45; then the gas B in another gas cabinet 41 is introduced, and the pressure at this time can be recorded as PA+PB by the pressure indicator. According to the ideal gas equation, it can be known that the partial pressure ratio of the two gases in the container is the molar ratio of the two gases. That is, the pressure difference can be controlled by the pressure reducing valve to control the mass flow of the gas, and the proportion of the mixed gas can be accurately adjusted according to the pressure indicator of the mixing chamber, so as to achieve the purpose of adding a single type or various types of mixed gases in different proportions.

[0087] By setting up the above-mentioned intake system 4, a mixed gas of a specific ratio can be provided quickly and accurately according to specific needs, so that different mixed gas ratios can be given through repeated experiments, and the difference in the fluidity of the lead-mystal alloy under different ratios can be compared, so as to find the optimal mixed gas ratio.

[0088] In the present application, through the above-mentioned settings, either a single gas can be injected or a mixture of multiple gases can be injected; a check valve is set between the pressure reducing valve and the gas cabinet to prevent the gas from flowing back into the gas cabinet; a one-way valve and an air pump are set in front of the mixing chamber to prevent the gas from flowing back and at the same time enable the device to add the required gas in real time as needed during the experiment. Steps for adding gas: 1. Look at the index of the pressure indicator at this time, recorded as P1, and then open the pressure reducing valve in front of the gas cabinet of the required gas to pass the required gas, and obtain the required amount of gas according to the change in the pressure index. 2. Close the pressure reducing valve, turn on the pump 6, and pump in the required gas. Because there is a check valve, there is no need to consider the backflow of hot gas in the gas circulation pipeline located in the lead-bismuth alloy circulation pipeline, until the index of the pressure indicator returns to P1, that is, the gas filling is completed, and the pump is turned off.

[0089] In addition, each time the mixed gas is configured by injecting gas into the mixing chamber 44 through the gas cabinet 41, the total amount of the configured mixed gas is sufficient for one cycle experiment, so there is no need to configure the mixed gas of the same proportion again.

[0090] Before the experiment begins, the gas circulation pipeline can be set to a vacuum state. After the experiment, the gas in the gas circulation pipeline is introduced into the gas collection system 7 through the exhaust fan 9.

[0091] If the gas ratio needs to be changed after one experiment, the gas needs to be replaced. If the gas ratio does not need to be changed, the gas does not need to be replaced, and there is no need to collect gas to the outside through the gas collection pipeline.

[0092] In a preferred embodiment, Figure 3As shown in , the gas collection system 7 includes a separation chamber 71 and a storage bottle 72, and a gas collection check valve 73 is provided between the separation chamber 71 and the storage bottle 72;

[0093] Preferably, a plurality of storage bottles 72 are provided, which are respectively connected to different positions of the separation chamber 71 through pipelines.

[0094] A permeable membrane 74 is provided in the separation chamber 71; the separation chamber 71 is divided into a plurality of independent spaces connected in sequence by the permeable membrane 74, and each of the independent spaces is connected to at least one storage bottle 72, so that when gas needs to be extracted from the independent space, the gas can be stored in the storage bottle 72.

[0095] The present invention also provides a passive natural circulation lead-bismuth gasification method, in which a mixed gas of a predetermined proportion is prepared through the following steps:

[0096] Step a, injecting gas from a gas cabinet 41 into a mixing chamber 44 through a pressure reducing valve 43, and recording the pressure value in the mixing chamber 44 through a pressure indicator 45;

[0097] Step b, injecting the gas in another gas cabinet into the mixing chamber 44 through another pressure reducing valve, and then recording the pressure value in the mixing chamber 44 through the pressure indicator 45, and calculating the mass ratio of the mixed gas in the mixing chamber 44 according to the change of the pressure value.

[0098] Preferably, according to the desired mixed gas composition, gases from other gas cabinets can be optionally continued to be injected into the mixing chamber 44, that is, if the mixed gas contains three components, three corresponding gas cabinets are opened respectively, and the three gases are injected into the mixing chamber in sequence.

[0099] Preferably, the mass ratio of each component in the mixed gas is determined by:

[0100] Step 1, recording the gas pressure in the mixing chamber 44 after the gas A in the first gas cabinet 41 is injected into the mixing chamber 44, recorded as PA;

[0101] Step 2, record the change of gas pressure in the mixing chamber 44 when gas B in the second gas cabinet 42 is injected into the mixing chamber 44, and record the total gas pressure at this time as PA+PB, where PB represents the pressure generated by gas B alone, and the ratio of PA to PB is recorded as the mass ratio of gas A to other B.

[0102] By the same token, the gas C in the third other cabinet 42 can be added. Correspondingly, during the process of adding gas C, the gas pressure in the mixing chamber 54 is the total pressure, which can be expressed as PA+PB+PC. The mass ratio of gases A, B, and C is equal to the ratio of PA, PB, and PC.

[0103] In a preferred embodiment, in the passive natural circulation lead-bismuth gasification method, after the mixed gas is prepared, the mixed gas in the mixing chamber 44 passes through the air intake check valve 5 and the pump 6 and then enters the temperature rising section 11 of the gas circulation pipeline through the air intake pipe port 2; by adjusting the power of the pump 6, the gas entry speed can also be adjusted, so as to obtain the influence of different flow rate gases on the passive natural circulation.

[0104] The gas moves upward in the temperature rising section 11 of the circulation pipeline and is heated by the lead-bismuth alloy in the lead-bismuth alloy circulation pipeline, then passes through the hot gas section 12 and the temperature falling section 13 in sequence, is cooled in the temperature falling section 13, and finally returns to the temperature rising section 11 via the cold gas section 14, thereby circulating in the gas circulation pipeline;

[0105] When the gas in the gas circulation pipeline needs to be exhausted, the gas outlet check valve 8 and the exhaust fan 9 on the gas collection pipeline are opened, so that the gas in the gas circulation pipeline enters the gas collection system 7 through the gas collection pipe port 3.

[0106] Preferably, the gas entering the gas collection system 7 is treated as follows:

[0107] The control gas passes through the multiple separation chambers 71 in the gas collection system 7 in sequence. After all the gas in the gas collection pipeline enters the separation chamber 71, the gas in the separation chamber 71 farthest from the gas inlet end of the gas collection system 7 is first injected into the storage bottle 72, and then the gas in the separation chamber adjacent to the farthest separation chamber is collected, and so on, and finally the gas in all the separation chambers is collected into different storage bottles 72. More preferably, an exhaust fan is provided between the separation chamber 71 farthest from the gas inlet end of the gas collection system 7 and the storage bottle 72, and the exhaust fan works continuously, so that the separation chamber is in a negative pressure state, so that the gas in the gas collection system continues to diffuse toward the separation chamber farthest from the gas inlet end of the gas collection system 7, so as to separate the gas components.

[0108] Example:

[0109] A natural circulation secondary loop device designed by the Institute of Nuclear Thermal Safety and Standardization of North China Electric Power University was selected. It is known that the flow rate of the lead-bismuth alloy in the circulating flow device is 2m / s, and the constant pressure specific heat capacity of the lead-bismuth fluid is 144.9KJ / Kg, the thermal conductivity is 12.1W / Km, and the dynamic viscosity is 0.00169Kg / ms;

[0110] The passive natural circulation lead-bismuth gasification device provided in the present application is installed on the lead-bismuth alloy natural circulation flow device, and the device includes a gas circulation pipeline, and the gas circulation pipeline includes a heating section, a hot gas section, a cooling section and a cold gas section connected in sequence; the heating section is installed in the ascending section of the lead-bismuth alloy circulation pipeline, and the cooling section is installed in the descending section of the lead-bismuth alloy circulation pipeline; an air inlet pipe opening is opened on the heating section, and a gas collecting pipe opening is opened on the cold gas section.

[0111] The gas is deployed through the intake system and enters the gas circulation pipeline at different flow rates and the same pressure under the action of the intake check valve and the pump. The flow rate and heat transfer capacity of the lead-bismuth alloy under different mixed gas conditions are observed and recorded, so as to compare the effects of mixed gases with different flow rates on the flow rate of the lead-bismuth alloy. The temperature of the rising section of the experimental lead-bismuth alloy is 400℃.

[0112] The experimental results are shown in the following table:

[0113]

[0114]

[0115] A gas is prepared through the intake system 4, and under the action of the intake check valve and the pump, it enters into the natural circulation flow device of the lead-bismuth alloy at different flow rates and the same pressure, and the flow rate of the lead-bismuth alloy under different mixed gas conditions is observed and recorded, so as to compare the effects of mixed gases with different flow rates on the flow rate of the lead-bismuth alloy; the temperature of the rising section of the experimental lead-bismuth alloy is 400°C.

[0116] The experimental results are shown in the following table:

[0117]

[0118] A gas is prepared through the intake system 4, and under the action of the intake check valve and the pump, it enters into the natural circulation flow device of the lead-bismuth alloy at different flow rates and the same pressure, and the flow rate of the lead-bismuth alloy under different mixed gas conditions is observed and recorded, so as to compare the effects of mixed gases with different flow rates on the flow rate of the lead-bismuth alloy; the temperature of the rising section of the experimental lead-bismuth alloy is 500°C.

[0119] The experimental results are shown in the following table:

[0120]

[0121] According to the results of the embodiment, when other conditions remain unchanged, increasing the volume share of the injected gas is conducive to enhancing the natural circulation capacity, while decreasing the volume share of the injected gas makes the radial temperature distribution of lead and bismuth more uniform, the average temperature decreases, and the heat transfer capacity weakens;

[0122] Keeping other conditions unchanged, changing the injection gas velocity has no significant effect on the temperature distribution, while the total pressure has a local effect but little overall impact;

[0123] At the same temperature, the greater the argon injection flow rate, the greater the natural circulation flow rate of lead and bismuth in the loop. At different temperatures, when the same argon injection flow rate is injected, the higher the temperature, the greater the natural circulation flow rate of lead and bismuth.

[0124] The purpose of injecting gas is not to increase the total pressure of the lead-bismuth fluid, but to change the average density of the lead-bismuth alloy, reduce the lifting pressure drop, and thus increase the driving pressure head of the circuit and enhance the natural circulation capacity.

[0125] In summary, the passive natural circulation lead-bismuth gasification device and gasification method provided in this application can obtain the optimal gas addition ratio, gas flow rate, and gas flow rate that are most suitable for nuclear reactors.

[0126] The present invention has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, the present invention may be subjected to a variety of substitutions and improvements, all of which fall within the scope of protection of the present invention.

Claims

1. A passive natural circulation lead-bismuth gasification device, characterized in that: The device comprises a gas circulation pipeline, which is installed on a lead-bismuth alloy circulation pipeline; A lead-bismuth alloy coolant flows in the lead-bismuth alloy circulation pipeline, and a heater and a heat exchanger are arranged on the lead-bismuth alloy circulation pipeline; The gas circulation pipeline comprises a temperature rising section (11), a hot gas section (12), a temperature falling section (13) and a cold gas section (14) which are connected in sequence; The temperature rising section (11) is installed in the rising section of the lead-bismuth alloy circulation pipeline and is located after the heater; The temperature reduction section (13) is installed in the descending section of the lead-bismuth alloy circulation pipeline and is located after the heat exchanger; The hot gas section (12) passes through the wall of the lead-bismuth alloy circulation pipeline, one end of which is sealedly connected to the top of the temperature rising section (11), and the other end of which is sealedly connected to the top of the temperature falling section (13); The cold air section (14) passes through the wall of the lead-bismuth alloy circulation pipe, one end of which is sealedly connected to the bottom end of the temperature rising section (11), and the other end of which is sealedly connected to the bottom end of the temperature falling section (13); An air inlet opening (2) is provided on the temperature rising section (11). The cold air section (14) is provided with an air collecting pipe opening (3). Injecting gas into the gas circulation pipeline through the gas inlet pipe port (2), and exhausting the gas in the gas circulation pipeline through the gas collecting pipe port (3); The device further comprises an air intake pipeline and an air collecting pipeline, wherein an air intake system (4), an air intake check valve (5) and a pump (6) are sequentially arranged on the air intake pipeline, and the air intake pipeline is in communication with the air intake pipe port (2); An air collection system (7), an air outlet check valve (8) and an exhaust fan (9) are sequentially arranged on the air collection pipeline; the air collection pipeline is connected to the air collection pipe port (3); adjusting the composition ratio of the gas through the air intake system (4); The air intake system (4) comprises a gas cabinet (41) and a mixing chamber (44); The gas cabinet (41) is connected to the mixing chamber (44) via a pipeline, and an air intake check valve (42) and a pressure reducing valve (43) are provided on the pipeline; A plurality of gas cabinets (41) are provided, each gas cabinet (41) stores a type of gas, and the types of gases in different gas cabinets (41) may be the same or different; The multiple gas cabinets (41) inject gas into the mixing chamber (44) one by one; A pressure indicator (45) is provided on the mixing chamber (44); the pressure indicator (45) is used to output the pressure value on the mixing chamber (44) in real time, so as to adjust the ratio of the mixed gas according to the data of the pressure indicator (45); Collecting and storing gas in the gas circulation pipeline through the gas collection system (7); The gas collection system (7) comprises a separation chamber (71) and a storage bottle (72), and a gas collection check valve (73) is provided between the separation chamber (71) and the storage bottle (72).

2. The passive natural circulation lead-bismuth gasification device according to claim 1 is characterized in that: A plurality of storage bottles (72) are provided, each of which is connected to different positions of the separation chamber (71) through a pipeline.

3. The passive natural circulation lead-bismuth gasification device according to claim 1 is characterized in that: A permeable membrane (74) is arranged in the separation chamber (71); the permeable membrane (74) divides the separation chamber (71) into a plurality of sequentially connected independent spaces, and each of the independent spaces is connected to at least one storage bottle (72).

4. A passive natural circulation lead-bismuth gasification method, characterized in that: The method is implemented by the passive natural circulation lead-bismuth gasification device as claimed in any one of claims 1 to 3; The gas in the mixing chamber (44) passes through the air intake check valve (5) and the pump (6) and then enters the temperature rising section (11) of the gas circulation pipeline through the air intake pipe opening (2); The gas moves upward in the temperature rising section (11) of the circulation pipeline and is heated by the lead-bismuth alloy in the lead-bismuth alloy circulation pipeline, then passes through the hot gas section (12) and the temperature falling section (13) in sequence, is cooled in the temperature falling section (13), and finally returns to the temperature rising section (11) via the cold gas section (14), thereby circulating in the gas circulation pipeline; When it is necessary to exhaust the gas in the gas circulation pipeline, the gas outlet check valve (8) and the exhaust fan (9) on the gas collection pipeline are opened, so that the gas in the gas circulation pipeline enters the gas collection system (7) through the gas collection pipe opening (3).

5. The passive natural circulation lead-bismuth gasification method according to claim 4, characterized in that: The gas in the mixing chamber (44) is configured by the following steps: Step a, injecting gas from a gas cabinet (41) into a mixing chamber (44) through a pressure reducing valve (43), and recording the pressure value in the mixing chamber (44) through a pressure indicator (45); Step b, injecting gas from another gas cabinet into the mixing chamber (44) through another pressure reducing valve, then recording the pressure value in the mixing chamber (44) through a pressure indicator (45), and calculating the mass ratio of the mixed gas in the mixing chamber (44) based on the change in the pressure value.

6. The passive natural circulation lead-bismuth gasification method according to claim 4, characterized in that: The gas entering the gas collection system (7) is treated as follows: The control gas sequentially passes through a plurality of separation chambers (71) in the gas collection system (7). After all the gas in the gas collection pipeline enters the separation chamber (71), the gas in the separation chamber (71) farthest from the gas inlet end of the gas collection system (7) is first injected into the storage bottle (72), and then the gas in the separation chamber adjacent to the farthest separation chamber is collected, and so on, and finally the gas in all the separation chambers is collected into different storage bottles (72).

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